Structural diversity of bimetallic rhodium and iridium half sandwich dithiolato complexes

Subtle changes in the structure of the backbone can lead to profound differences in the binding modes of dithiolato ligands in rhodium and iridium half sandwich complexes.

Disulfide passivation of the Ge(100)-2 × 1 surface

Understanding the bonding of sulfur at the germanium surface is important to developing good passivation routes for germanium-based electronic devices. The adsorption behavior of ethyl disulfide (EDS) and 1,8-naphthalene disulfide (NDS) at the Ge(100)-2 × 1 surface has been studied under ultrahigh vacuum conditions to investigate both their fundamental reactivity and their effectiveness as passivants of this surface. X-ray photoelectron spectroscopy, multiple internal reflection-infrared spectroscopy, and density functional theory results indicate that both molecules adsorb via S-S dissociation at room temperature. Upon exposure to ambient air, the thiolate adlayer remains intact for both EDS- and NDS-functionalized surfaces, indicating the stability of this surface attachment. Although both systems resist oxidation compared to the bare Ge(100)-2 × 1 surface, the Ge substrate is significantly oxidized in all cases (17-57% relative to the control), with the NDS-passivated surface undergoing up to two times more oxidation than the EDS-passivated surface at the longest air exposure times studied. The difference in passivation capability is attributed to the difference in surface coverage on Ge(100)-2 × 1, where EDS adsorption leads to a saturation coverage 17% higher than that for NDS/Ge(100)-2 × 1.

A novel recyclable sulfur monoxide transfer reagent

[reaction: see text]. Trisulfide 2-oxide 11 has been prepared from disulfide 9 via reduction to the corresponding dithiol and subsequent trapping with thionyl chloride. Heating trisulfide oxide 11 in the presence of dienes results in transfer of sulfur monoxide to form cyclic unsaturated sulfoxides 13 in good to excellent yields, along with recovery of disulfide 9. A Pummerer reaction can be used to convert the cyclic sulfoxides into thiophenes.